Carton blank



Oct. 30, 1962 N. F. HAAcK 3,061,167

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NE/L F.' HAACK ATTORNEY United States Patent Utilice 3,d6l,167 Patented Oct. 30, 1962 3,061,167 CARTON BLANK Neil F. Haack, Menasha, Wis., assigner to American Can Company, New York, N.Y., a corporation of New .Ierse y Filed June 13, 1961, Ser. No. 116,729

2 Claims. (Cl. 229-37) This invention relates to a carton construction and more particularly to a novel gluing panel which is a construction element of one piece paperboard carton blanks which are folded and glued to form a collapsed, open-ended shell or tube by the carton manufacturer and shipped in the collapsed condition to packagers who complete the setting-up of the carton, insert the product to be packaged and close the carton, thus producing .a finished package with product enclosed.

A high percentage of the one-piece paperboard cartons used in the packing of a wide variety of products are shipped by the carton manufacturer in the form of collapsed glued shells in the interests of economy in shipping space. The blanks from which such cartons are formed are provided with a series of wall panels interconnected by a number of parallel score hinge lines and having a glue panel hinged to one side edge of the blank. The glued shell is formed in collapsed condition by folding the blank back on itself along certain of the score lines and adhering the glue flap to a wall panel adjacent the edge of the blank opposite to that to which the glue panel is hinged.

Adhesive is most commonly applied to the glue panel by means of a rotating glue wheel which is partially submerged in a bath of the liquid adhesive. A carton blank conveyor is employed which brings the glue panel of the carton blank into contact with the peripheral surface of the glue wheel after it has emerged from the adhesive bath bearing a surface film of adhesive. As the carton blank is moved past the glue wheel, the rotating wheel applies .a film of adhesive to the glue panel progressively from the leading edge to the trailing edge of the glue panel.

As the carton blank passes out of contact with the glue wheel, the adhesive film tends to string out between the glue wheel surface and the glue panel trailing edge. When the thin adhesive thread breaks, the surface tension of the adhesive pulls the portion of the thread clinging to the glue panel into a small bead of adhesive which projects from the trailing edge of the glue panel.

In the subsequent operations, the carton blank is folded to bring the adhesive-bearing glue panel surface into underlying relationship to the Wall panel at the remote edge of the blank and pressure contact is maintained until the adhesive sets up, thereby completing the fabrication of the glued carton shell in collapsed condition.

Unfortunately, it often happens that the bead of excess adhesive, previously mentionedas protruding from the trailing edge of the glue panel, comes into contact with the inside surface of an overlying wall panel and forms an adhesive bond therewith so that the shell is effectively cemented in the collapsed condition. The carton shell then does not open up satisfactorily on high-speed machinery designed to set-up, ll and close the carton and jam-ups occur with consequent damage to the cartons and often loss of the product being packaged.

The above difficulty is avoided by the present invention, which comprises a modification in the construction of the glue panel so that the bead of adhesive, protruding from the glue panel trailing edge, is prevented from forming a firm bond between the interior surface of the wall panels which are in contact with each other in the collapsed shell and consequent malfunctioning of the carton in the setup and filling operations is prevented. The invention is best understood by reference to the following description and to the accompanying drawings, in which:

FIGURE l is a plan view of a representative carton blank embodying the modified glue panel of this invention,

FIGURE 2 is an enlarged cross-sectional view of a folded and glued carton shell in the collapsed state.

FIGURE 3 is a fragmental plan view of a collapsed carton shell with a portion of the uppermost Wall panel cut away,

FIGURE 4 is a portion of a cross sectional View, somewhat enlarged, along line 4-4 of FIGURE 3, and including the portion of the uppermost panel which in FIGURE 3 was cut away,

FIGURE 5 is a view similar to FIGURE 4 except that the carton embodies a conventional glue panel instead of the improved glue panel of this invention, and

FIGURE 6 is a perspective view of the gluing apparatus showing conventional means of applying adhesive to a carton glue panel.

As illustrated in the accompanying drawings, the carton blank of the present invention is provided with a series of parallel score lines 1, 2, 3 and 4 serving to delineate a front wall panel 5, a rear wall panel 6, a pair of end wall panels 7 and 8, and a glue panel 9 extending from the side edge of rear wall panel 6. End closure panels 11, 12, 13 and 14 are hingedly attached to the top and bottom edges of the respective wall panels and are provided with suitable locking elements 13 and 19.

As best shown in FIGURES 1 and 3, an edge of the glue panel 9 adjacent to the score line 1 hingedly connecting the glue panel to the rear wall panel 6 is provided with a substantially U-shaped cutout 21, with the remaining portions 22 and 23 of the glue panel edge area extending in arm-like projections on either side of the cut-away area. The U-shaped cut-out area 21 performs an important function in the formation of the carton blank into a glued shell prior to the final carton set-up, filling and closing operations, as herein fully explained.

In forming the carton blank into a finished carton, liquid adhesive is applied to the outer surface of the glue panel 9 and the blank subsequently folded along score line 2 so that the rear wall panel 6 overlies both end wall panel 8 and a portion of front wall panel 5, and the glue panel 9 also overlies a portion of front wall panel 5, the inner surfaces of the respective panels being in contact. The adhesive applied to the glue panel then lies exposed on its outer surface. End wall panel 7 is then folded back along score line 4 so that its inner surface contacts the adhesive-coated outer glue panel surface and this contact is maintained under suitable pressure until the adhesive sets up, thereby forming a glued collapsed carton shell as shown in FIGURES 2 and 3. Cartons are generally shipped by the manufacturer in the collapsed state to conserve shipping space and are set-up, filled with a product and closed on high-speed packaging machinery in the packagers plant.

The step of applying adhesive to the exterior surface of the glue panel is conveniently carried out on a straightline gluer in which the carton blank is conveyed horizontally past a rotating glue wheel 26, in FIGURE 6, which dips in a bath Z7 of liquid adhesive 28, excess adhesive being removed by the metering wheel 29. As the carton advances, the glue wheel first contacts the glue panel at its leading edge and progressively applies adhesive to the glue panel as the carton moves forward, contact between the glue wheel and the glue panel being maintained until the trailing edge of the glue panel passes by the glue wheel 26. In FIGURE 6, the carton blank is represented as just having passed the glue wheel.

VDue to its viscosity and elastomeric properties, the

liquid adhesive tends to string out slightly between the glue wheel 26 and the trailing edge of the glue panel 9 until the elastomeric limit of the liquid adhesive thread is exceeded and the thread breaks. Surface tension of the adhesive pulls that portion of the thread remaining on the glue panel into a small bead 30 of adhesive clinging to the glue panel trailing edge as shown in FIGURE 6. In the carton blank of the present invention, this adhesive bead 30 forms at the bottom of the cut out portion 2l of the glue panel 9 between the arm-like projections 22 and 23.

When the carton blank is subsequently folded as previously described into collapsed shell form with glue panel 9 adhered to the inside surface of end wall panel 7, the pressure which is applied to maintain intimate contact of the glued areas during the adhesive setting period deiiects the portions of the front wall panel 5 and the end wall panel 7 which are unsupported by the interposed glue panel 9 into contact with each other as shown in FIGURES 4 and 5 In a carton blank having a conventional glue flap (FIGURE 5) this deflection of the carton wall panels tends to squeeze the adhesive bead 30 out into a thin film extending into the area of direct contact between wall panels 5 and 7', indicated at B in FIG- URE 5, allowing the formation of a firm bond between these surfaces in that area.

As is Well known in the adhesive art, a firm glue bond may be formed between two surfaces only if they are brought into intimate contact so that the adhesive film between the two surfaces is very thin. At points B and B' in FIGURES 4 and 5, respectively, the carton wall panels are substantially in direct contact with one another and the presence of an adhesive film between the panels at this point leads to the formation of a firm bond. At points A and A', however, panels 5 and 7 are separated by a distance substantially equal to the thickness of the glue panel 9, which may range from about 0.01 in. to 0.05 in. and even substantially higher in the case of corrugated paperboard stock. It has been found that even if an adhesive is interposed between the wall panels 5 and 7 at this point and in contact with both panels, there is no appreciable bond formed between these panels at this point, presumably because on drying or hardening, the adhesive shrinks sufficiently to withdraw from contact with one or the other of the wall surfaces. It will be appreciated that any such shrinkage of the adhesive film at points B and B would be imperceptible due to the extreme thinness of the film in this area.

In forming a glued carton shell from the blank incorporating the present invention as shown in FIGURE 4, the adhesive bead 30 is retained within the pocket formed by the cut-out area 21 in the glue panel. The arm-like projections 22 and 23 prevent the deflection of wall panels 5 and 7 toward each other in the immediate vicinity of the adhesive bead and the bead therefore is not squeezed out into the area B, where panels 5 and 7 are in close enough contact to allow the formation of a strong adhesive bond between them. The cut-out portion 21 of the glue panel thus prevents the undesirable cementing of the shell in its collapsed condition. As previously explained, any contact of the adhesive between panels 5 and 7 at point A is immaterial since at this point the panels in question are held apart by the arm-like projections 22 and 23 and thus cannot be bonded securely together at this point.

As will be apparent from FIGURES 4 and 5, if the carton incorporates score lines impressed in the stock in close proximity to the position of the glue panel trailing edge in the collapsed glued shell, the necessity for the cutout area 21 in the glue panel is intensified since even a slight deflection of the Wall panels 5 and 7 will bring the scored areas into the intimate contact necessary for the formation of a firm adhesive bond.

Although the improved glue panel construction of my invention has been described and illustrated in connection with a carton blank for a single compartment package having conventional closure iiaps and locking means, its utility is not so limited. The invention has also found utility in the manufacture of cartons which include a wall panel extending between the front and rear wall panels intermediate the two end wall panels and serving as a partition to separate the carton into multiple compartments. The partition panel normally is hingedly connected to a section of the rear wall and has an appended glue panel adapted for adhesion to the opposed wall panel. Cartons having a partition panel of this type are particularly susceptible to the formation of stickers wherein an excess of glue on the trailing edge of the partition glue panel bonds the front and rear walls together, cementing the shell in collapsed condition and causing jam-ups in the setting-up, filling and closing operations performed on high-speed machinery. Inclusion of the improved glue panel construction of my invention has substantially eliminated this difficulty in commercial production.

My improved glue panel may be utilized on any carton blank having at least a pair of Wall panels with a glue panel hingedly connected to one of them and adapted to be adhered to the other of the pair of wall panels to form a collapsed sleeve or tube, the simplest such construction consisting of two hingedly connected panels with a glue ap hinged to one of the two panels and adapted to be adhered to the other panel to form a flat, sleevelike envelope open at both ends. The number or arrangement of the panels is immaterial so long as the blank includes a glue panel adapted for adherence to a wall panel to form a collapsed carton shell or tube. The presence or absence of end closure flaps and locking or sealing means as features of the carton construction is similarly immaterial to the present invention and carton lblanks both with and without these features are considered within the scope of my invention.

I claim:

1. A carton blank suitably cut and scored to provide a series of wall panels hingedly connected at their lateral edges by parallel score lines, said series including front and rear wall panels, a pair of side wall panels and a glue panel hinged to a lateral edge of one of said wall panels, an end edge of said glue panel adjacent to said glue panel hinge connection being provided with a substantially U- shaped notch to provide a pocket area for the retention of excess adhesive extending beyond the central portion of said end edge of the glue panel upon adhesion of the glue panel to a Wall panel.

2. A carton blank suitably cut and scored to provide a pair of Wall panels and a glue panel hingedly attached to one of said wall panels, said blank being adapted to be folded to bring said glue panel into underlying relationship to the other of said wall panels and to have said glue panel adhered to said other wall panel thereby forming a flat sleeve, an end edge of said glue panel adjacent said hinge connection to said one wall panel being provided with a substantially U-shaped notch to provide a protective pocket area for the retention of excess adhesive extending beyond the central portion of said end edge of the glue panel and within said notched area upon adhesion of said glue panel to said other wall panel to form said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 2,337,198 Holy Dec. 21, 1943 2,396,150 Bouville Mar. 5, 1946 3,003,679 Andrews Oct. 10, 1961 

